(19)
(11) EP 0 920 196 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
14.03.2001 Bulletin 2001/11

(43) Date of publication A2:
02.06.1999 Bulletin 1999/22

(21) Application number: 98309454.1

(22) Date of filing: 18.11.1998
(51) International Patent Classification (IPC)7: H04N 5/235, H04N 9/04
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 21.11.1997 JP 33665297
21.11.1997 JP 33665397

(71) Applicant: Matsushita Electric Industrial Co., Ltd.
Kadoma-shi, Osaka 571-8501 (JP)

(72) Inventors:
  • Serizawa, Masayuki
    Yokohama 224-0054 (JP)
  • Tabei, Kenji
    Sagamihara-shi, Kanagawa-ken 229-0006 (JP)

(74) Representative: Senior, Alan Murray 
J.A. KEMP & CO., 14 South Square, Gray's Inn
London WC1R 5LX
London WC1R 5LX (GB)

   


(54) Method and imaging apparatus for generating a dynamic range expanded video signal


(57) An imaging circuit generates a first video signal with a first exposure interval and a second video signal with a second exposure interval substantially at the same time, the second exposure interval being shorter than the first exposure interval, the first and second video signals respectively having first and second dynamic ranges which are different but continuos. The first video signal is synchronized with the second video signal. An exposure ratio between the first and second exposure intervals is detected. A gain of the second video signal is adjusted according to the exposure ratio. A combined video signal is generated from the first and second video signals according to a mixing control signal indicative of a mixing ratio between first and second video signals and levels of the first and second video signals to have an expanded dynamic range such that the first dynamic range is connected to the second dynamic range with difference in gains of the first and second video signals adjusted for linearity. An edge enhancement signal may be gain-controlled or coring-controlled according to the mixing control signal or the exposure ratio. The similar apparatus and method for color signals are also disclosed. The output dynamic range for a display is limited by a non-linear process.






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